Jax -
One of the other members sent me another suggestion too. Check to make sure the machine is draining correctly. You never know what may be stuck down there under the wash plate. If it's not, the water moving around as the machine spins can cause the noises you heard. With the cover removed, fill the machine then set it to spin. You can see through the outer tub if there is any water still caught in there swirling around while the machine is spinning. If so, the pump, a hose or the plastic housing where the drain hoses connect may be clogged. This would certainly cause the violent stops as the tub locks up against the force of moving water. You can see from under the machine where all of the hoses connect at the back...it looks like a small plastic box. Could be a sock or hankie caught somewhere.
Is your water pump one piece or two? A two piece pump has the pump unit attached to the motor by two metal clamps at each side of the plactic pump housing, and sits directly underneath the motor. A one piece is, obviously, all one piece.
Yes, the info on the spin brake is the repair manual if you need it.